A bridge rectifier is a type of electrical circuit in which four rectifying paths are connected between each of two alternating current (AC) input paths and each of two direct current (DC) output paths to provide the same polarity of output for either polarity of input (half wave). The rectifying paths usually include one or more diodes, which are quite inefficient and considerably affect the overall efficiency of power conversion from AC energy to DC energy. The inefficiency arises from the forward voltages of the diodes, which may be up to 1 volt or more. As at least two diodes are connected in series at any time during operation of a bridge rectifier, the voltage loss caused by the diodes may approximately be between 0.8 and 2.5% in common power supply circuits whose input voltage is somewhere between 85 and 265 volts (V). This inefficiency caused by the diodes is often considered to be too much.